From 04ca0652814bed46eba6a5782c9284908ca5f3f8 Mon Sep 17 00:00:00 2001
From: Peter Boyle <paboyle@ph.ed.ac.uk>
Date: Thu, 29 Feb 2024 20:09:11 -0500
Subject: [PATCH] Only one rank opens

---
 benchmarks/Benchmark_usqcd.cc | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/benchmarks/Benchmark_usqcd.cc b/benchmarks/Benchmark_usqcd.cc
index 526e5659..7b1fddd4 100644
--- a/benchmarks/Benchmark_usqcd.cc
+++ b/benchmarks/Benchmark_usqcd.cc
@@ -842,10 +842,14 @@ public:
 
 int main (int argc, char ** argv)
 {
-
-  FP = fopen("Benchmark_usqcd.csv","w");
   Grid_init(&argc,&argv);
 
+  if (GlobalSharedMemory::WorldRank==0) { 
+    FP = fopen("Benchmark_usqcd.csv","w");
+  } else {
+    FP = fopen("/dev/null","w");
+  }
+
   CartesianCommunicator::SetCommunicatorPolicy(CartesianCommunicator::CommunicatorPolicySequential);
 #ifdef KNL
   LebesgueOrder::Block = std::vector<int>({8,2,2,2});